白色“淡水Akoya珍珠”和Akoya珍珠的谱学及成分特征  

Spectrum and Chemical Composition Characteristics between White“Freshwater Akoya Pearls”and Akoya Pearls

作　　者：赵雪娇 李立平[1,2] 陈照敏 李思琪 ZHAO Xuejiao;LI Liping;CHEN Zhaomin;LI Siqi(Gemmological Institute,China University of Geosciences,Wuhan 430074,China;Hubei Gems and Jexvelry Engineering Technology Research Center,Wuhan 430074,China;Jiangsu Gold and Jewelry Testing Center Co.,Ltd.,Nanjing 210000,China)

机构地区：[1]中国地质大学(武汉)珠宝学院,湖北武汉430074 [2]湖北省珠宝工程技术研究中心,湖北武汉430074 [3]江苏省黄金珠宝检测中心有限公司,江苏南京210000

出　　处：《宝石和宝石学杂志（中英文）》2023年第2期32-41,共10页Journal of Gems & Gemmology

基　　金：中国地质大学(武汉)珠宝检测技术创新中心开放基金(项目编号CIGTWZ-2021036)。

摘　　要：近年来我国珍珠市场中出现了一类小颗粒(粒径3~10 mm)的优质的白色淡水有核珍珠,由于其与白色Akoya珍珠(简称Akoya)在外观上的相似性,被商家称为“淡水Akoya珍珠”(简称F-Akoya)。本文选取来自诸暨市场的F-Akoya及Akoya样品进行了常规宝石学测试、光致发光光谱测试、三维荧光光谱测试和LA-ICP-MS测试,对比分析得出了两类珍珠的的常规宝石学鉴定特征、谱学特征及成分特征,发现:(1)尽管它们外观相似,都具有强珍珠光泽和很高的正圆率,但Akoya珍珠层较薄,表面常有鱼鳞纹、褶皱,而F-Akoya珠层较厚,缺少鱼鳞纹;(2)PL光谱总体荧光强度(F)与文石主峰强度(A)的比值F/A值发现,F-Akoya通常在1~5范围内,远低于Akoya的13~169;(3)三维荧光光谱显示,F-Akoya的荧光光谱发光中心Ex/Em范围为350~380 nm/420~440 nm,且荧光强度很高,而Akoya的发光中心在350~400 nm/430~480 nm范围内,且荧光强度极低;(4)LA-ICP-MS测试发现,F-Akoya明显富Mn,而Akoya明显富Na、Mg、K、Sr, F-Akoya稀土模式为LREE相对HREE轻微富集,而Akoya则相反;(5)成分分析结果反映珍珠的微量和稀土元素含量与它们生长环境有关。通过三元成分图和稀土元素配分模式图,可以较好的区别两类珍珠。In recent years,a kind of high-quality white freshwater nucleated pearls in small size(3-10 mm)has appeared in pearl market in P.R.China,which is commercially called"freshwater Akoya pearl"(F-Akoya)because of its similar appearance to white Akoya pearl(Akoya).In this paper,F-Akoya and Akoya pearl samples from Zhuji market were collected and analyzed by conventional gemmological test,photoluminescence(PL)spectrometer,three-dimensional fluorescence(3D FR)spectrometer and LA-ICP-MS.Although F-Akoya pearls are similar to Akoya pearls in appearance,they are clearly different in the following aspects:(1)In terms o£the thickness and morphology of the nacreous layer,the Akoya is thinner with fish-scale-like grains and fold-like flaws on its surface,while the F-Akoya is thicker without fish-scales-like grains;(2)In terms of the F/A value,namely,the ratio of the overall fluorescence intensity(F)of the PL spectra to the main peak intensity of aragonite(A),the F-Akoya usually ranges in 1 to 5,much lower than the F/A range of Akoya(13 to 169);(3)In terms of the luminescence center Ex/Em in the 3D FR spectra,the F-Akoya ranges in 350〜380 nm/420〜440 nm with high fluorescence intensity,while the Akoya ranges in 350〜400 nm/430〜480 nm with low fluorescence intensity;(4)In terms of minor elements shown by LA-ICP-MS,F-Akoya is obviously rich in Mn,while Akoya richs in Na,Mg,K,Sr;(5)In terms of the rare earth element pattern,F-Akoya is enriched in LREE,while Akoya shows the opposite.The composition analyses revealed that the composition of the F-Akoya and Akoya depends on their growth water environment.Importantly,they can be distinguished by the ternary component diagrams and REE partition pattern diagram.

关 键 词：珍珠 “淡水Akoya珍珠” Akoya珍珠 光致发光光谱 LA-ICP-MS 鉴别 

分 类 号：TS93[轻工技术与工程]